1. Field
Aspects of embodiments of the present invention relate to an adhesive film for polarizing plates, an adhesive composition for polarizing plates, a polarizing plate comprising the same, and an optical display including the same.
2. Description of the Related Art
A liquid crystal display includes a liquid crystal panel and polarizing plates attached to both surfaces of the liquid crystal panel. Each of the polarizing plates includes a polarizer and a protective film formed on one or both surfaces of the polarizer to protect the polarizer. The polarizing plate is attached to the liquid crystal panel via an adhesive film for polarizing plates.
An adhesive film for polarizing plates is required to have good adhesive strength to a protective film. An adhesive film exhibiting poor adhesion is vulnerable to shrinkage and/or expansion of a polarizing plate when the polarizing plate is exposed to high temperature and/or high humidity conditions, thereby causing poor image quality of a liquid crystal display. In addition, the adhesive film for polarizing plates is required to suppress detachment of the polarizing plate from a liquid crystal cell and generation of bubbles under high temperature and/or high humidity conditions. The adhesive film for polarizing plates must satisfy each of high adhesive strength to protective films, good durability, and high peel strength.
The adhesive film for polarizing plates is produced by coating an adhesive composition to a predetermined thickness, followed by aging the adhesive composition. Generally, aging is performed at room temperature (for example, 23° C.) for about 3 days to 7 days. In order to reduce the aging period, aging may be performed at a constant temperature of 35° C. In this case, however, a separate aging room is required. Moreover, since the adhesive film is cut after aging at room temperature (for example, 23° C.), even in the case where aging is performed at a constant temperature, there is a problem of deterioration in productivity. Moreover, the adhesive composition can suffer from increase in viscosity in a blended state before coating, thereby causing deterioration in process stability.
The background technique of the present invention is disclosed in Japanese Patent No. 5,738,967.